South African sprinter Oscar Pistorius, known as the “Blade Runner,” is making history as the first double amputee runner at the Olympic Games. Some critics, including Olympic gold medalist Michael Johnson, claim Pistorius’s prosthetic legs give him an unfair advantage over his opponents. Mathew Parente, clinical director of the University of Hartford’s Prosthetics and Orthotics program, explains why he disagrees with this opinion.
Do Oscar Pistorius’s prosthetic legs give him an advantage over his competitors?
Oscar actually has to use larger muscle groups to accomplish the same tasks that smaller muscles normally do. The muscles down in the foot and ankle complex that help control our foot are smaller muscles. Oscar no longer has those muscles so he has to use larger muscles, which requires more energy to accomplish the same motion.
It requires between 30 and 50% more energy for him to do the same task as someone who has both limbs intact. For a 200 pound person, that would be the equivalent of carrying around a 100 pound backpack all day to do the same task.
I can take this and correlate it back to writing. If I were to write a message, I’m going to use my hand and use smaller muscles within in my hand and write on the paper. But in order to write on a blackboard, I would have to use larger muscle groups. Our shoulders get fatigued a lot quicker than our hand does.
There are no moving parts to the legs. There’s something called energy response or energy return, but that just comes from the deflection or the repositioning of the carbon. The return is so minor for what his energy consumption is, it doesn’t make a lot of difference.
Do you envision a time when using a prosthesis could be an advantage?
We are really far away from that. At a point when we’re using artificial or external muscles or engines to produce the same functions, that would be a time when they might want to reconsider allowing prostheses in competition. We’re years away from that. There are so many systems involved: the position of the feet and the body, shock absorption, everything the foot does for us. We can’t accommodate for those in a prosthesis at this point. I don’t see athletes going out and seeking amputation because of the potential problems they would face, like socket issues. The weight would have to be transferred onto another part of the body that it wasn’t initially intended for because as the runner steps, all that weight that goes down to the ground has to come back up into the runner’s body. The athlete would have lost all of the elements of the foot and ankle complex that absorb shock and help to preposition our foot to accommodate motion and everything else.
What impact will Oscar Pistorius have on the prosthetics and orthotics industries?
I think it’s great that he’s competing. It’s a very positive thing where patients and a lot of people will see a man who is missing both legs below his knee and is out there competing at the highest level.
There are going to be a lot of stories out there about Oscar and I just hope this inspires future prosthetists, orthotists and engineers who see this to say, “I think I have an idea to make a better foot or make a more advanced prosthesis.” I think it’s wonderful and I hope that it really inspires future generations of clinicians as well as engineers, designers and researchers to say “we can do better.”